The present invention relates to room air conditioners and, in particular, it concerns a design in which the room air conditioner is split into indoor and outdoor units interconnected using an interface unit mounted in an external wall.
It is known that the room air conditioner is an inexpensive, and thus desirable, alternative to the split-type air conditioning system in which the indoor and outdoor sections are separated physically and housed in separate cabinets. The installation of a room air conditioner requires a large opening in the external building wall, such that the room air conditioner is relatively noisy. Moreover, the capacity of a room air conditioner to heat or cool is generally limited to a single room because of space limitations and the additional noise produced by higher capacity units.
Split type air conditioners, unlike room air conditioners, generally produce characteristically lower noise levels in the room. Other potential advantages include the capacity to heat or cool several rooms, and a requirement for a relatively small opening in the external building wall.
A conventional room air conditioner will be described with reference to the drawings to particularly point out the characterizing features thereof. FIG. 1 is a sectional side view of a conventional air conditioner of the vertical type; FIG. 2 is a sectional view taken along the line IIxe2x80x94II of FIG. 1. As shown in these figures, the room air conditioner includes a cabinet 1, the interior of which is divided into an indoor portion 10 and an outdoor portion 11 by a partition plate 12 secured to a bottom 9 of the cabinet 1. A motor 5 is supported on a side of partition plate 12, which faces the outdoor portion 11 of cabinet 1 and includes horizontally-disposed (i.e., parallel to bottom 9) rotary shaft 5a. A portion of rotary shaft 5a penetrates partition plate 12 and extends into the indoor portion 10.
Mounted in the indoor portion 10 of cabinet 1 are a centrifugal fan 3 secured to rotary shaft 5a, a spiral casing 4 secured to partition plate 12 and disposed in enclosing relation to centrifugal fan 3, and an indoor heat exchanger 2 located adjacent to spiral casing 4 on a side thereof opposite centrifugal fan 3. Housed in the outdoor portion 11 of cabinet 1 are a propeller fan 6 secured to rotary shaft 5a of fan motor 5, an outdoor heat exchanger 7 disposed in spaced juxtaposed relation to propeller fan 6, a cover 15 interconnecting propeller fan 6 to outdoor heat exchanger 7, and a compressor 8 mounted on the bottom 9. Inlet ports 1a for introducing air into the interior of the cabinet are formed at opposite sides of the outdoor portion 11 of cabinet 1.
In the room air conditioner described above, fan motor 5 and compressor 8 are actuated, such that a refrigerant compressed in compressor 8 has its temperature raised. The heated refrigerant is supplied to outdoor heat exchanger 7 and is cooled by a stream of air B produced by the rotation of propeller fan 6. Subsequently, the cooled refrigerant is supplied to indoor heat exchanger 2, where the refrigerant is expanded to cool indoor heat exchanger 2, such that a stream of air A produced by the rotation of centrifugal fan 3 is cooled by indoor heat exchanger 2. The refrigerant is then returned to compressor 8.
There are several disadvantages associated with the above-described room air conditioner of the prior art, including:
a. The arrangement in which indoor heat exchanger 2, centrifugal fan 3, fan motor 5, propeller fan 6 and outdoor heat exchanger 7 are interconnected necessitates mounting all the aforementioned components in a single cabinet 1 together with compressor 8, resulting in the exposure of the room occupants to noisy mechanical system components.
b. The aforementioned arrangement in which indoor heat exchanger 2, centrifugal fan 3, fan motor 5, propeller fan 6 and outdoor heat exchanger 7 are interconnected such as to necessitate the mounting of all the aforementioned components in a single cabinet 1 together with the compressor 8, necessitates the provision of a large opening in the external building wall for installation of the air conditioner.
c. The effective cooling capacity of the air conditioner is generally limited to a single room, due to the high-level noise emissions and other design constraints.
There is therefore a recognized need for, and it would be highly advantageous to have, a low-cost room air conditioner having the advantages of split type air conditioners: low-level noise emissions, small opening requirement, and capacity to heat or cool more than a single room.
The present invention is a room air conditioner in which the indoor and outdoor sections are housed in separate cabinets and an interface unit is provided to interconnect various components including the heat exchangers, and to couple the indoor centrifugal fan to the fan motor housed in the external cabinet.
According to the teachings of the present invention there is provided, a room air conditioner in which noisy system components are housed external to the room, resulting in lower exposure of room occupants to noise.
According to yet another aspect of the present invention there is provided a room air conditioner with means for connecting the external and internal sections which permits the use of a minimally sized opening in the external building wall.
According to further features in the described preferred embodiments, the reduced noise exposure to room occupants provided, and the use of a minimally sized external building wall opening, permit the installation of a larger capacity room air conditioner which is capable of handling the air conditioning load of more than one room. This is accomplished in one preferred embodiment of the invention by means of connecting the interior unit air outlet port to a two-way damper and to air ducting so as to convey conditioned air to one or more additional rooms.
According to yet further features in the preferred embodiments, there is provided a room air conditioner having means of introducing fresh air into the room through the interface unit, while permitting installation using a minimally sized external building wall opening. According to yet further features in the preferred embodiments, there is provided a room air conditioner with many of the advantages of split-type air conditioners such as low noise production, high capacities capable of handling more than one room, and small external wall opening needed for installation, with minimal thermal efficiency losses due to the small distance between the indoor and outdoor heat exchangers.
According to yet further features in the preferred embodiments, there is provided a room air conditioner having means of using condensate water to humidify heated indoor air in the heating mode and to cool the exterior heat exchanger (condenser) in the cooling mode.
The present invention successfully addresses the shortcomings of the existing technologies by providing a design for reducing indoor noise levels of the room air conditioner and eliminating the need for providing a large installation opening in the external building wall. Consequently, the design allows the implementation of inexpensive, larger capacity room air conditioners that are capable of air conditioning more than one room.